Stroke, tPA & Statistical Chance

A healthy dose of fatalism should accompany any patient experiencing the symptoms of stroke when presenting at an emergency room for treatment. Assuming the facility is not a stroke center, with enhanced diagnosis resources and treatment options for combating the effects of ischemic stroke, one’s prospects for full or partial recovery could well depend upon the confidence in and willingness of the E.R. physician to administer tissue plasminogen activator or "tPA," a thrombolytic agent, capable of recanalizing a passage through an arterial clot in the brain tissue.

Although the use of tPA is recommended by the American Heart Association as a first line treatment for ischemic stroke the use of the drug is controversial because of significant risk of inducing intracranial hemorrhage and other organic damage in a small but significant number of patients.

Although favored by many neurologists, where the current existence of intracranial hemorrhage and other contraindications are not present, the use of tPA is not favored among many E.R. Specialists and its effectiveness is disclaimed by a position paper of the American Academy of Emergency Medicine:

It is the position of the American Academy of Emergency Medicine that objective evidence regarding the efficacy, safety, and applicability of tPA for acute ischemic stroke is insufficient to warrant its classification as standard of care. Until additional evidence clarifies such controversies, physicians are advised to use their discretion when considering its use. Given the cited absence of definitive evidence, AAEM believes it is inappropriate to claim that either the use or no-use of intravenous thrombolytic therapy constitutes a standard of care issue in the treatment of stroke.

Grounds for "no-use" recited by E.R. specialists include lack of statistical support for efficacy, potential serious or even fatal side effects, lack of neurological or radioneurological support, and lack of ability to meet the recommended 3-hour time window from onset of stroke symptoms, because of other demands in the emergency room and a lack of confidence in the efficacy of tPA.

Recent studies seem to support the use of tPA for stroke victims in qualifying patients as the standard of care.

On average, if you don’t treat 100 people who suffer from stroke and who meet the criteria for receiving tPA, 21 will die within three months, 20 will be able to return home with normal functioning, and the remainder will have some impairment. But if those some 100 people are given tPA, 17 will die within 3 months, 31 will return to normal functioning and the remainder will suffer less impairment than those who did not receive the drug.

–  Dr. Phillip A. Scott, Assistant Prof. Emergency Medicine, University of Michigan

Although some emergency room physicians would prefer not to undertake the risk of causing intracranial hemorrhaging by administering tPA, for the right patients (without any indication of existing hemorrhage), the risks favor the use of the drug.

But, while doctors are taught the ancient oath, "First do no harm," they must also learn that in an era of scientific examination of effective therapies, "sometimes to do nothing is to do harm."

–  Dr. Phillip A. Scott

The courts have sometimes struggled over what to do with the statistical nuances and risks of the use or non-use of a particularly dangerous drug that can in many but not all cases improve the outcome of the onset of ischemic stroke. See Joshi v. Providence Health System of Oregon, 149 P.3d 1164 (2006) (court ruled 30% probability of survival insufficient to meet Oregon’s "but for" rule of causation and refused to impose liability upon E.R. physician for failure to administer tPA to stroke patient); Young v. Memorial Herman Hospital System, 2006 WL 1984613 (S.D. Texas) (in Texas, a plaintiff must show at least a 51% chance of avoiding injury to establish causation.)

In an unscientific survey of reported decisions and settlements it appears that malpractice cases for failure to administer tPA to stroke victims are running about 10 to one to those cases alleging damage from wrongful administration of tPA. The rise of stroke centers and their experience with the use of tPA appears to be having an impact in the courts. See Keylon v. Hill (Tenn. App. 2003) (directed verdict for defendant E.R. physician reversed on appeal, where neurologist testified as to the standard of care: "I’ve already testified that at the institution here we see that approximately 70 percent of the patients who have strokes and get tPA and are candidates to get tPA and get it do significantly or totally improve.")

It would appear prudent for emergency room physicians to look hard at their hospital protocols and procedures for the treatment of stroke victims and, if qualifying for receipt of the drug and presenting within the recommended three hour time frame from onset to either treat the patient with tPA or remove the patient to a designated stroke center that will.

Comments

[Miriam SKydell]

My mother had a stroke a week ago and was presented in the emergency room with total right side paralysis and an inability to formulate her thoughts into words though she understood whaqt as being asked of her. She made it to the hospital within an hour of her stoke and TPA was administerd. Exactly an hour after the drug was administerd the paralysis revearsed itself 90%. Today one week later my mom has 95% of her strngth back, 99% of her speech and no notable assymetry in her face. The drug was a miracle saver for her.

[Agronegócio]

Parabéns pelo blog, abraços!

[K Taylor]

3 1/2 months ago my 68 year old husband had a pulminary embolism, which showered both lungs. He was administered tPA after testing and consultation in the ER. He is well-educated and a bright person. I've noticed in the last month that he is exibiting loss of focus and memoory. Side effects fortPA are brain bleed. Is it possible that tPA compromised his mind?

[William Kubofcik]

The drug was a complete disaster for my Dad... within ten minutes of the TPA being administered...he had a brain hemorage... we never were told that this was a possibility... He had to get brain surgery...and 9 days later he is still in a coma-like state...